Ophthalmometer.



4 SHEETS-SHEET l.

PATBNTED JUNE 9, 1908.

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J. H. SUTGLIFFE. OPHTHALMOMETER.

APPLIOATION FILED AUG. z3. 1007.

76 2X `ZQ No. 000,500. PATENTED JUNE 9, 1908.

J. H. SUTGLIPPB. OPHTHALMOMETBR.

APPLICATION FILED AUG. 23, 1907.

Ll*SHEETS-SHEET 2.

ummm.' j' 6 W WMM *W SHI No. 890,580. PATENTED JUNE 9, 1908. J. H. SUTGLIPFE.

OPHTHALMOMBTER. APPLICATION FILED AUG.23,1907.

4 SHEETS-SHEET a.

7W@ .2.1. Mh/f J. H. SUTGLIFFE.

OPHTHALMOMETBR.' APPLICATION FILED AUG. 23, 1907.

PATENTED JUNE 9, 1908.

4 SHEETS-SHEET 4.

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I 75; @c m? |11 /ffv 7.9@ u 77a/ 77 i To all whom rMuay concern:

UNITED STATES PATENT OFFICE.

JOHN HAMER SUTCLIFFE, OF LONDON, ENGLAND, ASSIGNOR TO-GEORGE LONDON, ENGLAND.

Nofseoso.

CULVER LTD., OF

O PHTHALMOMETER.

Patented June 9, 1908.

Application filed Aug-ust 23, 1907. Serial No. 389,838.

Be it known that I, JOHN HAMER Srrr- CLIFFE, a subject of the King of Great Britain and Ireland, residing at 199 Piccadilly, in 'the county of London, England, have invented certain new and useful Improvements in Ophthalmometers, ofwhich the following ,isa specification, reference being had therein to the accompanying drawings.

This invention relates to ophthalmometers such as are employed by Opticians for measuring the curvature of the convex surfaces of the eye, and more especially for measuring the curvature of the cornea in different meridians and thus determining the amount and axis of corneal astigmatism.

In instruments of the kind referred to, the reflection in the convex corneal surface of an illumined object known as the mire is viewed through a telesco e furnished withmeans for rendering visib e to an observer a double or multiple image of this reflection; and the curvature of the refiecting surface in any meridian is estimated by the amount of adjustment requisite to bring the inner peri heries of a pair of images on that meridlan into exact contact with each other. The adjustment referred to has heretofore been effected either by moving the mire in the direction of the optical axis ofthe telescope moving the doubling device in the axial direction so as to vary the separation of the images which it produces.

Now this invention has reference mainl to a new method of producing the double or multiple images in question, according to which these images are formed and moved by means of an exceedingly weak lens system that is arranged as a component of the telescope objective and is divided into portions movable in relation to each other transversely to the axis of the telescope.

In order that my said invention may be more clearly understood and reduced to practice, it is hereinafter ,described with reference to the accompanying drawings, wherein Figure 1 is a longitudinal vertical section of an ophthalmometer in accordance therewith; Fig. 2 is a plan of the same,- partly in section; Fig. 3 is an end elevationviewed from the side of the patient 5 Fig. 4 is an end elevationV viewed from the side of the observer; Figs. 5 and 6 are transverse eleva- *representations of the glasses respectively shown in Figs. 5 and 6,' Fig. 9 is a representation ofthese glasses in combination; F1 10 represents an alternative constructiona detail; and Figs. 11 and 12 are diagrammatic views of the multiple images of the mire as seen bythe observer when the telescope 1s respectively in and out of focus, when these images have been brought into contact.

Referring now tov the drawings; the telesco e 1, which can be focused by means of a mil ed head 2 in the usual manner, is mount- ,y

ed on a support 3 th'at is verticallyadjustable by means of a milled head 4 w1th1n a hollow standard 5 su ported on a base 6; this base being prefera ly of trian ular form, cast or otherwise'formed integra ly with the standard 5, and formed with apertures 7, so as to afford stability andrigidity without undue increase of weight. The telescope 1 is furnished with the usual eye-piece 8,.and with a pair of lenses 9, 10,4 which in combination With the doubling or multiplying lens system `interposed between them, constitute a compound objective. On the end of the telescope nearest the patient there lis mounted the o aque casing 11, the interior of which is suitaEly illuminated, as by means of electric glow lamps 12, while its face 13, is furnished with a translucent portion 14, that constitutes the mire and is preferably of the form shown inFig. 3, consisting of a circle having at the vextremities of its vertical and horizontal diameters L-shaped projections.

The apparatus for producing multiple images ofthe mire, and for effecting the approximation and separation of these images, which constitutes the most important feature of this invention, is most clearly shown in Figs. 5 to 9 of the drawings. This ap aratus, which is mounted on both sides o a base plate .15 arranged within a casing 16 of somewhat oval form, preferably comprises a pair of cylindrical lenses of equal power and small curvature, say about diopter, that are crossed at right angles, so as to form an equivalent for a spherical lens of correspondf there is viewed\through it the reection of ingly low power. Each of these lenses is di vided lin the direction of its length into three plpKrtions, of which Vthe two outer portions are ed, while the central portion is movable lengthwise to effect the ap roximation and separation of the images. hese central and marginal portions are respetively numbered 17,17a and 18, 18, as shown in Figs. 7 and 8, wherein the dotted lines ly, indicate the axial directions of the cylindrical surfaces. The glasses 17, 18 are respectively mounted in frames 19, 20, that slide in guides 19a, 20a, secured on o posite sides of the base 15 and are provide with racks 21, 22 with which there 'engage pinions 23, 24. The arrangement of racks and pinions may obviouslyT be considerably varied; that shown in Fig. 2 of the drawings,wherein the pinions 23, 24 are respectively rotated by\ concentric milled heads25,v 26, possesses, however, the advantages of .compactness and ease of manipulation, while the milled heads are lmoreover so located that they can be rotated to adjustthe position -by means of small clamps 30 screwed images by these portions.

-f glasses without distracting the eye of the 25 l patient.

With the pinions .23, 24, there are respectlvelyconnecteda ointer 27 and an annular index 28 both visib e through a slot 29 in the casing 16.

The marginal glasses 17a, '18a are kept in or otherwise attached to the base plate 15; these clamps serving also as screws to stop out the overlapping portions of the glasses 17, 18a that are shaded in Fig. 9 and to prevent the formation of an additional image or In addition to or as a substitute for,'the clamps 30, there may be employed on each side of the base plate 15 an opaque shield 31v having a cross-shaped y aperture 32.

For the purpose of explaining theoperation of the instrument herembefore described it will for the present be assumed that the telescope 1 1s correctly foouSed, andthat the mire in the cornea of a patient. If now the glasses 17, 18 are both in their central lens, there will be visible to the eye of the v observer a single image offthe mire. v,By

y nnage` moving the glass 17 upwards this image is doubled, the additional image thus roduced moving upwards with the lass. 1S ould the glass 1'8 now be moved to t e left the ori inal will move bodily to the left witIi while the image produced by the upward movement by the glass 17 will also be dou-r bledf By the' adjustment of the glasses 17., .18 there canthus be produced the' compound lmage shown in Fig. 11, consisting of the I three images a.,l b, c, of the mire in exac't contact with each other and by the amount of these adjustments the curvatures of the vverits marginal portions, when the lens is `out of focus, produce separate images. In consequence of this fact, unless the telescope 1 is accurately focused, the portions 5,5', c, c of Fig. 9, instead-of producing single images b, c, as shown in Fig. 11 wil produce double images-b, b', c, c', such as shown'in Fig. 12.

tact.' There is thus a positive test for correct focus,. totally inde endent of thev 'personal equation of the o server, with the result that one of the most troublesome sources of error in observation is eliminated.

The index 28 is preferably graduated with a scale of curvatures in diopters, and the movement of' the pointer A27 over this scale is obviously a dierential one, indicating directly by its position in relation to the zero of the scale the difference of curvature of the Wo corneal meridians under observation, and obviating the necessity for subtracting curvatures. An ophthalmometer in acordconsiderable advantage over' such instru'- ments as heretofore constructed-that the difference of curvature oftwo meridians at right an les-to each other can be directly dethe mire through a the second curvature.

1. In an ophthalmometer, a vided with an objective; a mire the re ectionof which in the jcornea of the eye lis adapted t0 ,be viewed through said telescope; and for producing a plurality of images thus viewed and effectingtheapproximation and separation of said images, an auxiliary lens jective and composed of portions movable in relation to each. other transversely toV th axis of said telescope.

2. In an ophthalmometer, a telescope tion of which in the cornea can be viewed through said telescope; and for producing` a lurality of images of said mire, an auxiliary divided into a central portion and marginal -portions movable relatively to said central portion transverselyv to the axis of said telescope. e Y 3. In an ophthalmometer, a telescope provided with an objective, a mire the reflection of which in the cornea can be viewed through said telescope; and, for doubling or termine withoutf the necessity vof rotating right angle tomeasur'e.A

telescope ro- In focusing the telescope should the central strip of a lens be removed,

These images need'not, of courseVbe in cone ance with thisinvention thus possesses the system arranged asfa component of said obrovidedwith 'an objective, a mire'the reecens system comprising a pair-oflenses each multiplying the image thus viewed, a pair of crossed cylindrical lenses each divided'longi4 v'tu-dinally into central and marginal portions movable in relation to each' other transversely tol the axis of the telesope. l 4. n an ophthalmometer, in'combination with a telescope and a mire whose relection Ain the eye can therethrou h be viewed; means for doubling or multip ying the image thus viewed comprising an auxiliary lens system embodying a pair of crossed lenses each divided 'longitudinally vinto central and marginal portions movable in relation to Veach other.transversely to' the axis .of the telescope. 5

5. In an ophthalmometer, a telesco e provided with an obj ective; a'mjre the re ection of which in the cornea of' the eye is adapted to be viewed through saidtelescope; for pro-- ducing a plurality of images thus viewed and effecting the approximation.l and separation of said images, an auxiliary lens system` arranged as a component of said objective and.

composed ofl portions movable in' relation to each other transverselyto the axis of said` telescope geared to one 0f said movable lens portions an index, and to another of said or-I tions apo'inter adapted to move over sai index to indicate the relative movement .of said portions.

6. In an ophthalmometer a mire consisting of a luminous circle having 4at the extremities of two of its diameters at right an les L- shaped extensions rojecting outwar sai circleimeansibr illuminatin sairmire; a telesco e concentric with sai mire and. .adapted or viewing the reflection thereof in the cornea; and means for producing a plurality of images f said mir'e andbringing'the L-shaped extensions of adjacent images into contact, comprisin a pair of lenses eachjdividedvinto v centra and marginal lportions some of which are movable in vrelatdionvto the remainderl transversely to the axis of the telescope( f Y 7. In an ophthalmometerfa mire consisting o'f a luminous circle havinglat the extremities of ytwo of its diameters at right angles L- shaped extensions proecting outwardl frein sai circleymeans or illuminatin sai mire; a telesco e concentric withsai mire and adapted or viewing the reliection thereof in the cornea; and-means for produding a plurality of images of-said mire 'and the L- shaped extensions'of ad1acent'ima es into contact, comprisin a pair of crosse' cylinvdrical lenses each videdlongitudinally intocentral and marginal portions relatively movable transversely to the axis of the telescope. l

from

of av luminous circle having at the extremities .of two of its diameters at right angles L- sha edextensions projecting outwardly from sai circle;'means tor illuminatin said mire; a telesco e concentric with sai mire and adapted or viewin the .reflection thereof in the cornea; means or'producingand adjusting three images of said mire, comprisin i a f air of crossed cylindrical lenses each divi ed ongitudinally into central and marginal portions relatively movable transversely to the axis of the telescope, and, for preventing the formation of a fourth additional image, clamps that also serve to support said marginal lens'portions. l 9. In an ophthalmometer, a mire consisting of a luminous circle having at the extremities of two/ of' its diameters at right angles L- sha ed extensions rojecting outwardly from sai circlemeans orilluminatin said mire;

,a telesco e concentric -with sai adapted or viewin the reflection thereof in -the cornea; means orproducing and adjusting three images of said mire, comprisin a pair of crossed cylindrical lenses each divi ed ongitudinally into central and marginal portions relatively movable transversely to the axis ofthe-telescope, and, for reventing the formaticnl of a fourth additional image, clamps that 'also serve to support said marginal lens portions; eared to one of `said transversely movable ens portions an index, Y

and to the other of said portions a pointer movable over said inkdex.

10. In an ophthalmometer, a telescope furnshed with 'v an objective; a luminous mire whose reflection in the cornea can be viewed through said telescol e; means for illuminating. said ,mire; for' oubling said -reection when thus viewed on one corneal.-meridianA and'briI ing into -contactthe pair of images so forme a lens divided into relatively movable central and marginal portions; for doublingsaid reflection on a second corneal meridian at rht angles to vfirst-mentioned mev'ridian and ringing into contact this second mire and 'pair' of imagesfa second lens-similarly di- 8. In an ophthalmometer, a mire .`:o1 1 sis'ting,

jportions and consequently the dil?-Y rwhereof I affixjny signature J l 

